I'm very interested in all those invitational tournaments that were held before the ATP Tour Era (1990) and that are usually not sanctioned by the ATP. Those tournaments that interest me the most are those for which 4 match wins are needed in order to get the title. SO 16-man draws or 8-man ones in a RR+SF+F format.

I'm still wondering why this tournament seems to be ignored by everyone. Atptennis.com has listed all the previous editions of the ToC. OK I know, 1990 was the year in which the ATP gained control over most open tournaments but yet in the ATP Tour era, they have listed the Grand Slam Cup which was invitational (0 ranking points), so why not listing ToC '90?

Incidentally, Lendl won another edition of the Toronto Molson Light Challenge in 1984, defeating Noah in the final: 6-0 6-2 6-4. I suppose it's the same format as in 1981 but need confirmation. What happened in 1983?

I've edited the OP because I made a stupid mistake that only I could have made. Peter McNamara did not reach the final of the Melbourne Mazda exo in 1981 because he was defeated by Gene Mayer in the semi (and I had the info !!). Now I've learnt that he went on to beat Teltscher in the final, too. (source: straitstimes.com)

Mayer and Teltscher seem to have been specialists of that event because they were the two players beaten in the semi in 1982, Mayer by Gerulaitis (he had a back injury that day) and Teltscher by Lendl.